HIV-1 Tropism Determination Using a Phenotypic Env Recombinant Viral Assay Highlights Overestimation of CXCR4-Usage by Genotypic Prediction Algorithms for CRRF01_AE and CRF02_AG
Figure 2
Detection of minority CXCR4 and CCR5 using variants within mixed viral populations.
Mixtures containing known proportions of pNLAD8 and pNL4-3 (100∶0, i.e. pure NLAD8, 99∶1, 97.5∶2.5, 95∶5, 90∶10, 80∶20, 50∶50, 20∶80, 10∶90, 5∶95, 2.5∶97.5, 1∶99, 0∶100, i.e. pure NL4-3) were PCR-amplified and used to generate recombinant viruses. U87.CD4.CCR5 and U87.CD4.CXCR4 indicator cells were infected with serial 2-fold dilutions (x-axis) of mixtures (z-axis) to determine the threshold for detection of minority variants. Infection was quantified 48 hours after infection by measuring luciferase activity in cell lysates (y-axis). Black bars report infection of U87.CD4.CXCR4 cells and grey bars report infection of U87.CD4.CCR5 cells. Panels A and B report the same data, oriented to focus on NL4-3 minority variants (A) or on NLAD8 minority variants (B).
